The present invention relates to apparatus for patching multiple electrical lines to permit changing connections to equipment.
U.S. Pat. No. 4,037,186, together with the references cited therein, disclose connecting and switching modules for switching multiple lines between electrical equipment. In one specific application discussed therein, multiple-line connection between a local equipment and a modem may be broken and alternative connections may be established by inserting plugs at the ends of patch cords into sockets in the front of each connecting and switching module. Switching to accomplish the breaking and connecting is performed by a plurality of magnetic reed switches actuated by a magnet moved into its actuating position by the act of inserting the plugs.
As noted in the references, a plurality of connecting and switching modules are conventionally mounted side by side in, for example, a standard rack. This permits patch-cord interconnection between equipment connected to any pair of connecting modules. In this manner, operation of a modem or other equipment may be monitored, faults may be isolated and substitute modems or test equipment may be connected as desired to maintain operation of a system.
I have discovered that the prior art frequently employs a different type of connecting and switching modules for each application. Each different type conventionally represents a completely different design from all others. That is, the circuit board required to satisfy each communications protocol is unique. Thus, a manufacturer supplying a broad line of connecting and switching devices must bear the cost of designing, manufacturing and stocking an extensive line of connecting and switching devices. The number of unique designs may exceed ten or twenty.
In analyzing the differences between the conventional designs, I have discovered that they include different monitoring electronic circuits and different connectors for making the connections to modems and local equipment. The remaining functions of the conventional designs are common.
it is desirable to have as much flexibility at the rack level as possible. In the prior art, most rack-mounted patching systems employ 16 connecting and switching modules side by side in a standard 19-inch rack. One popular type of connector used in a V.35 communications system is so larg that installing 16 modules in a standard rack is prevented by interference between the hoods of connector plugs inserted into the connectors on the modules. It has become conventional to employ a smaller number of connecting and switching modules in a V.35 system. Instead of the 16 modules standard in most other systems, a V.35 system usually can accommodate only 12 modules to avoid connector crowding.
The differences between module mounting in a V.35 system from that in, for example, an RS 232C or an X.21 system present operational drawbacks, besides the cost of the unique design. For example, it is not possible to mix and match V.35 modules in a rack containing other types of modules. The extra space required for V.35 modules precludes this. Thus, even if only one or two V.35 modules are required, a user must provide a full rack of 12 modules to satisfy the need.